A recent study conducted by researchers at the Karlsruhe Institute of Technology (KIT) reveals that rising temperatures could make groundwater undrinkable for up to 75 million people by 2100. The study, which examined two climate scenarios—SSP 2–4.5 and SSP 5–8.5, representing different socioeconomic pathways and greenhouse gas concentrations—found significant increases in groundwater temperatures over the next 76 years.

The midrange scenario, SSP 2–4.5, predicts a rise of 3.8 degrees Fahrenheit, while the extreme scenario, SSP 5–8.5, forecasts an increase of 6.3 degrees Fahrenheit. Dr. Susanne Benz, one of the study's authors from the Institute of Photogrammetry and Remote Sensing at KIT, emphasized the urgency of protecting groundwater and finding sustainable solutions to mitigate the impacts of climate change.

"Depending on the scenario, several hundred million people could be affected by 2100," Benz stated. "Currently, around 30 million people live in regions where groundwater temperatures exceed the strictest drinking water guidelines, making it unsafe to drink without treatment."

The study suggests that by 2100, between 77 to 188 million people under SSP 2–4.5 and 59 to 588 million under SSP 5–8.5 could face challenges related to increased groundwater temperatures. This rise in temperature affects not only water quality but also chemical, biological, and physical processes critical to groundwater-dependent ecosystems and geothermal energy potential.

"Rising groundwater temperatures can increase concentrations of harmful substances like arsenic or manganese, posing health risks when groundwater is used as drinking water," Benz explained. "This is a significant concern for the drilling industry, which must adapt to these changing conditions."

The study highlights the importance of understanding how surface warming impacts groundwater, Earth's largest unfrozen freshwater reserve, across different regions and over time. Benz and her team simulated projected changes in global groundwater temperatures through 2100, creating maps that show expected warming rates at various depths.

The research indicates that regions with shallow groundwater tables and high atmospheric warming, such as parts of the United States and South America, will experience the most significant increases in groundwater temperature. In contrast, mountainous areas like the Andes and the Rocky Mountains, with deeper water tables, are expected to see less warming.

This study underscores the need for the water well drilling industry to develop and implement strategies to address these changes, ensuring safe and reliable access to groundwater for future generations. As the groundwater continues to heat, deeper water well drilling jobs may become more common to reach water sources at deeper levels.